This research examines the effect of hyperinsulinemia on protein phosphorylation using the euglycemic insulin clamp method. After baseline samples are obtained, insulin will be infused into the antecubital vein for 120 minutes. Glucose will be monitored every 5 minutes and glucose infusion adjusted accordingly. At the end of the study a muscle biopsy from the quadriceps muscle will be done. Results of experiments demonstrating one of several novel methods used to examine protein phosphorylation was presented at the 1997 meeting of the American Diabetes Association. We anticipate developing further methods for studying Tyr phosphorylation from tissue biopsies. If successful, these studies will open new avenues for clinical investigation of cell signaling processes.